ABB REQ650 1.3 IEC, Commissioning Manual

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LED Light-emitting diode
LNT LON network tool
MCB Miniature circuit breaker
MVAL Value of measurement
NCC National Control Centre
NOF Number of grid faults
NUM Numerical module
OCO cycle Open-close-open cycle
OCP Overcurrent protection
OLTC On-load tap changer
OTEV Disturbance data recording initiated by other event than start/pick-up
OV Over-voltage
Overreach A term used to describe how the relay behaves during a fault condition.
For example, a distance relay is overreaching when the impedance
presented to it is smaller than the apparent impedance to the fault
applied to the balance point, that is, the set reach. The relay “sees” the
fault but perhaps it should not have seen it.
PCI Peripheral component interconnect, a local data bus
PCM600 Protection and control IED manager
PC-MIP Mezzanine card standard
POR Permissive overreach
POTT Permissive overreach transfer trip
Process bus Bus or LAN used at the process level, that is, in near proximity to the
measured and/or controlled components
PSM Power supply module
PST Parameter setting tool within PCM600
PT ratio Potential transformer or voltage transformer ratio
PUTT Permissive underreach transfer trip
RCA Relay characteristic angle
RISC Reduced instruction set computer
RMS value Root mean square value
RS422 A balanced serial interface for the transmission of digital data in point-
to-point connections
RS485 Serial link according to EIA standard RS485
RTC Real-time clock
RTU Remote terminal unit
SA Substation Automation
SBO Select-before-operate
SC Switch or push button to close
SCL Short circuit location
SCS Station control system
SCADA Supervision, control and data acquisition
Section 10 1MRK 505 293-UEN B
Glossary
114 Breaker protection REQ650
Commissioning manual
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